Nice to Toulouse. Any must see stops/detours along the way?

If you cut across southern France and then head northwest to Toulouse following the E80, there is lots to see.
You might consider stopping at a small village such as Pezenas on the way. Lots of winding, cobbled streets and great shops and restaurants. There are also many fantastic, small wineries in this area if you like to partake.
You'll be near the Canal du Midi which is lovely in many spots along the way.
Collioure is a little out of your way but it's a lovely, old, seaside village that is shady, relaxed and has a beautiful waterfront.
The cathedral in Narbonne is well worth your time...it was only partially built but is stunning, especially when you consider what the size would have been had it been completed.
We also like the cathedral in Beziers...the town is a little sketchy but the view from the top of the tower is really breathtaking.
Carcassonne will be on your way if you travel in this direction - very touristy but still impressive.
Again, a little out of your way, but Lourdes is also not far from this route. It's a very impressive pilgrimage site as those things go.

There are so many places that it's hard to know where to begin. The South is filled with historic, charming and scenic spots. Anita has mentioned very worthy places to see. I wouldn't argue with any of them.

It gets down to personal preference on allocating limited time. I suggest that you get the Michelin Green Guides to Provence and to Languedoc-Roussillon. They provide guidance as to what there is to see, restaurants, places to stay and driving routes. I've found them invaluable. You can decide what you want to see based upon your own interests.

My own première place in the South is the Luberon-Bonnieux, Gordes, Roussillon. Spend at least one night there. If you do Verdon it won't even be a detour.

Montpellier-it's ok but unless you have a particular reason for visiting there I would save it. But honestly I've only ever driven through it to get people onto the TGV and we were running late so my impressions are no doubt somewhat skewed.

Thank you Anita and Lee. With the limited time we have we have to pick between Verdon or driving along the coast through quaint little towns. After looking at some of the photos of Verdon, we are highly inclined to drive via Verdon. Being a civil engineer myself I also want to cover the Millau Viaduct. We are planning to start from Nice in the morning (between 10 and 11 AM), drive through Verdon and stop for the night somewhere in the Manosque region (not sure if we can get further than that in one day). Next morning - drive to the Viaduct and then onto Toulouse. We will probably have time to see some of the small towns in the Millau region and also I can drive through Luberon-Bonnieux, Gordes, Roussillon.

Is that a good plan? I am do-it-all and see-it-all type of person so I tend to cramp as many things as I can... sometimes it gets crazy.

Thank you for your input.

Since you like to see everything possible, I'd recommend stopping in Nimes for a meal, and walking up the Roman Maison Carree and arena. I assume you know about the Pont du Gard - may be too far away from your proposed route.

The viaduc is well worth the detour. After you drive across, walk from the visitor center up to the observation point for a spectacular view. Chateau de Creissels in Millau gets high marks for rooms with a view of the bridge but I have no personal experience.

Though time clouds the memory, I know I was glad to have driven via Verdon and didn't feel I had missed out on the coast. If you'll be in Nice for a few days, you can easily side-trip along the coast from there.

I have driven both a few times.... and they are so completely different I would find it hard to choose one over the other. You might find less traffic driving to Verdon as the coast drive can be very slow and congested. But, if I had to make a choice I still don't think I could... would have to flip a coin:)